anti siphon valve

[MDeVito]

The anti siphon valve on my below deck fuel tank is shot and I need a new one. I have tried all of the marine supply stores around my area, but no one seems to have the right size. I need to find someone that sells one with a 3/8" hose barb and a 1/2" NPT on the other end. Can someone point me in the right direction?

 

[JB]

Re: anti siphon valve

Moving to Boats

 

[18rabbit]

Re: anti siphon valve

They are a common item in industrial applications. Common name is ‘check valve.’ Use brass, bronze or stainless for hydrocarbons / petrochemicals. Should cost around $6 unless it is on a boat...then the exact same critter is called an 'anti-siphon valve' and can cost 2 or 3 times as much.<br /><br />They are made by SMC, Nibco, Parker, Conbraco/Apollo.

 

[Chris1956]

Re: anti siphon valve

MDevito, I have heard recommendations from outboard authorities that you should not use these valves with outboards due to the risk of fuel starvation and the engine damage associated. My Merc Dealer also recommended that the screen on the bottom of the fuel pickup also be removed to allow easy reliable flow.

 

[18rabbit]

Re: anti siphon valve

Chris – the values are rated for opening pressure. These check values open with about ½-psi vacuum. They are a requirement on ALL gasoline fuel tanks used on boats in the US. They will not starve an outboard.<br /><br />Take a look at this thread from a few days ago:<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=005913

 

[MDeVito]

Re: anti siphon valve

Thanks for the info. on my fuel pickup I have a large mesh wire screen could that still reduce fuel flow?

 

[MDeVito]

Re: anti siphon valve

So where might I pick one of these guys up? I have found them, but not in a 1/2" pipe thread. If a use an adapter will it affect my fuel flow and how will my motor respond?

 

[ReelDrag]

Re: anti siphon valve

Just wondering, if you do away with the anti siphon valve and use a regular barbed fitting,will the fuel line lose it's prime faster due to the fuel siphoning back into the tank?

 

[ZmOz]

Re: anti siphon valve

You should be able to find one at any hardware store. It is a common plumbing item. I don't know what motor you have, but you would probably be just fine with a 3/8" valve.

 

[DaveM]

Re: anti siphon valve

The purpose of the anti-siphon valve is to prevent gas from being siphoned into the bilge in the event of something bad like gas line rupture. It is a coast guard required safety device. <br /><br />Personally, I prefer not to take chances when fuel is involved.